Philips CD300 no output
Hello folks!
So - I got this CD300 as a broken piece.
In my attempt to diagnose what's wrong with it - I have came so far:
at first, when powered on -- tray works and nothing else. replaced failed cap on PSU. testing every PSU power out line is correct regarding schematic.
next problem: a couple of dim lights on tray LEDs, no spin-up, no clock signal for tray LED panel. Disconnect panel and disc spins up. turned out to be dead LED driver. replaced, have lights, and can start playback.
when disc spins up -- everything seems to work fine, except there is no output.
as I have never before dug into audio repairs -- is there any advice except quitting the repair on the machine? what to look for?
I have read through schematic and tested chip Power connections. some are fine, but some below spec. from schematic - rest of components pass. (for given power rail)
I' m stuck.
thanks in advance.
Hello folks!
So - I got this CD300 as a broken piece.
In my attempt to diagnose what's wrong with it - I have came so far:
at first, when powered on -- tray works and nothing else. replaced failed cap on PSU. testing every PSU power out line is correct regarding schematic.
next problem: a couple of dim lights on tray LEDs, no spin-up, no clock signal for tray LED panel. Disconnect panel and disc spins up. turned out to be dead LED driver. replaced, have lights, and can start playback.
when disc spins up -- everything seems to work fine, except there is no output.
as I have never before dug into audio repairs -- is there any advice except quitting the repair on the machine? what to look for?
I have read through schematic and tested chip Power connections. some are fine, but some below spec. from schematic - rest of components pass. (for given power rail)
I' m stuck.
thanks in advance.
Last edited:
Ahhh a Phirips 😀
You say the disc spins up. Does it continue spinning at correct speed ? and can you select tracks etc. Does it really appear to be just no audio output ?
You say the disc spins up. Does it continue spinning at correct speed ? and can you select tracks etc. Does it really appear to be just no audio output ?
Switch machine on -- front panel top row lights up, disc stopped.
Press play - bottom row first LED lights up and disc spins up. you can hear "scratchy noise" (I think it´s looking for track) and then sound stops, disc speed not changing.
when you say this - there is the glitch that I cannot change tracks (I suppose next track is the same as play button)
^^^^^^^^^^^^^^^^^^^^^
wrong. while writing this I watched a YT video of guy showing his cd300.. next track is SELECT button, then Play again. misleading button names? or I'm getting something wrong here?
=====================
I found this one --LINK, would it be right to compare waveforms from SAA7030 and TDA1540 ?
==> when player is playing track for some time -- it stops. disc spins down. press play, starts again. is it some kind of timeout, or it just finishes first track.
==> I burned audio cd for testing -- may be the problem is there? does this player support burned discs?
=====================
I know it' s a lot of info, but any tips are appreciated. Don't want this one to win me. 🙂 most interesting part is that the guy said it was working before he sold it as broken. 😀 I'm thinking it was a lie. 😀
BR
Press play - bottom row first LED lights up and disc spins up. you can hear "scratchy noise" (I think it´s looking for track) and then sound stops, disc speed not changing.
when you say this - there is the glitch that I cannot change tracks (I suppose next track is the same as play button)
^^^^^^^^^^^^^^^^^^^^^
wrong. while writing this I watched a YT video of guy showing his cd300.. next track is SELECT button, then Play again. misleading button names? or I'm getting something wrong here?
=====================
I found this one --LINK, would it be right to compare waveforms from SAA7030 and TDA1540 ?
==> when player is playing track for some time -- it stops. disc spins down. press play, starts again. is it some kind of timeout, or it just finishes first track.
==> I burned audio cd for testing -- may be the problem is there? does this player support burned discs?
=====================
I know it' s a lot of info, but any tips are appreciated. Don't want this one to win me. 🙂 most interesting part is that the guy said it was working before he sold it as broken. 😀 I'm thinking it was a lie. 😀
BR
First tip 😀 Don't use any CDR (and CDRW may not even be supported) for testing. All normal music discs give an identical RF signal for test purposes and are perfect as test discs.
Before getting heavy with fault finding establish the basics. If the disc appears to spin at approx the right speed then 99.9999% it is at the right speed. Disc motor servo faults either cause the disc to spin at a million miles an hour, take off backwards or spin at erratic speeds with lots of pulsing and kicking.
Check the RF on a scope. If its at the correct amplitude but totally blurred then it could be that the tracking servo isn't working. That's blurred as in it looks like the scope isn't triggered and the rf is mega jittery on the x axis and can't be resolved at all into the classic diamond pattern.
Before getting heavy with fault finding establish the basics. If the disc appears to spin at approx the right speed then 99.9999% it is at the right speed. Disc motor servo faults either cause the disc to spin at a million miles an hour, take off backwards or spin at erratic speeds with lots of pulsing and kicking.
Check the RF on a scope. If its at the correct amplitude but totally blurred then it could be that the tracking servo isn't working. That's blurred as in it looks like the scope isn't triggered and the rf is mega jittery on the x axis and can't be resolved at all into the classic diamond pattern.
is there any difference between CDR and regular music CD?? :O
yes, disc spins up and stays constant speed.
don't want to sound silly, but ir the RF signal same as FOC.ERROR for the CD300? if I'm wrong - where I should scope it?
schematic on page 22 shows pickup diodes, amplifier and all 4 summing up in FOC.ERROR.
am I right?
CD300 SM PDF HERE
yes, disc spins up and stays constant speed.
don't want to sound silly, but ir the RF signal same as FOC.ERROR for the CD300? if I'm wrong - where I should scope it?
schematic on page 22 shows pickup diodes, amplifier and all 4 summing up in FOC.ERROR.
am I right?
CD300 SM PDF HERE
or is it the HF signal? pin 7 of SAA7010?
by reading through repairfaq.org I would say its my first shot. after 3hours of googling and this forum -- I would say it's last option. 😀
I'm at work now so I cannot test both possibilities. 😀
BR
by reading through repairfaq.org I would say its my first shot. after 3hours of googling and this forum -- I would say it's last option. 😀
I'm at work now so I cannot test both possibilities. 😀
BR
Yes, CDR and CDRW are fundamentally different to normal pressed discs. A pressed disc is reflective with "transitions" from a 0 to a 1 occurring at each step or edge as a pressed "pit" changes to a "land". CDR's and RW's use dye that is burned away to create the transition edges. This are ill defined and the reflectivity is lower, and with CDRW very low giving rise to low amplitude RF.
You need to measure the RF at the point marked "hf" as shown.
(sorry for not replying earlier... a lot on 🙂)
Attachments
Sorry for the late reply.
So -- Scoped HF point, as suggested, right on the connector at the CD tray.
and the results were not promising. Want to mention in front, that it looks like someone has fu**ed the pots up. there are 3.
amplitude for the wave was ~1.3v, and I could barely see sine type waves. not to speak about the "eye-pattern"
I read your manual on adjusting them. also checked video on YT, I suppose it's yours.
also -- does it make any difference if I have digital oscilloscope? it's TDS-220 from Tektronix.
when properly adjusted -- should it trigger and stay calm, clear pattern, or it will jump around?
I will make screenshots next time I work on it.
BR
So -- Scoped HF point, as suggested, right on the connector at the CD tray.
and the results were not promising. Want to mention in front, that it looks like someone has fu**ed the pots up. there are 3.
amplitude for the wave was ~1.3v, and I could barely see sine type waves. not to speak about the "eye-pattern"
I read your manual on adjusting them. also checked video on YT, I suppose it's yours.
also -- does it make any difference if I have digital oscilloscope? it's TDS-220 from Tektronix.
when properly adjusted -- should it trigger and stay calm, clear pattern, or it will jump around?
I will make screenshots next time I work on it.
BR
I've never used a digital scope tbh but the TDS-220 seems OK spec wise. It should trigger easily on an RF signal. It makes me wonder whether there is a tracking issue.
YT 😀 Not me 🙂 I've never uploaded anything into there...
This shows how the RF should look,
http://www.diyaudio.com/forums/digital-source/226288-sony-cdp790-kss240-restoration-project.html
and any player is essentially the same give or take differences in amplitude. Your 1.3 volts sounds fine.
YT 😀 Not me 🙂 I've never uploaded anything into there...
This shows how the RF should look,
http://www.diyaudio.com/forums/digital-source/226288-sony-cdp790-kss240-restoration-project.html
and any player is essentially the same give or take differences in amplitude. Your 1.3 volts sounds fine.
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